Nasal mites are commonly found in hummingbirds (Apodiformes). In most cases, endoparasitic mites were reported to parasitize the respiratory system, particularly the anterior nasal chambers, larynx, trachea, lungs, and the air and conjunctival sacs. However, some mites are only carried by hummingbirds, because flowers serving as a nutrient source for these small mites, such as for Apodiformes, a tropical nectar-feeding in their natural habitat. From August 2012 to May 2014, humminbirds were captured using mist nets, and examined for the presence of nasal mites (identified according to specific keys) in the Pantanal, and Cerrado biomes, from the Mato Grosso state, midwestern Brazil. Overall, 76 Apodiform specimens, from the Trochilidae family were captured, and 20 female nasal mites, identified as being from the Rhinoseius genus, were collected from eight hosts (10.5%), of the following species: Amazilia fimbriata, Amazilia versicolor, Eupetonema macroura, and Thalurania furcata. The Rhinoseius spp. has been reported on, in many ecosystems in the Americas, including Brazil, however, this is the first report on Apodiformes from the Pantanal biome. Phoretic mites are not responsible for direct damage to the population of Apodiformes, as they are not pathogenic. However, they compete for food with hummingbirds and decrease the quantity of food available in the environment. They also affect the reproductive dynamics of plants, feed on pollen, and interfere with the intricacies of the biodiversity where they live.

In most reported cases, endoparasitic mites that inhabit the respiratory system of Apodiformes parasitize the anterior nasal chambers, larynx, trachea, lungs, and the air and conjunctival sacs (Amaral and Rebouças, 1974). However, in some cases the mites found are only carried, and dispersed by the Apodiformes, with flowers serving as a source of nutrients for these hosts in their natural habitat and for the mites (Proctor and Owens, 2000). Thus, the present study aimed to describe the occurrence of nasal mites in Apodiformes from the Pantanal and Cerrado biomes of the Mato Grosso state, midwestern Brazil.

2. Material and Methods

From August 2012 to May 2014, hummingbirds were captured as primary samples for another project on rickettsial infection spread from ticks of birds (Ramos et al., 2015). These Apodiformes were examined for the presence of ectoparasites that included nasal mites in two different biomes in the Mato Grosso state, including Pantanal and Cerrado biomes in the municipalities of Poconé and Chapada dos Guimarães. In each area, 10 mist nets (10 m long, 3 m high with 1 cm mesh holes) were opened on five days between 6:00 a.m. and 11:00 a.m., resulting in 3500 network hours throughout the study, and captured hummingbirds were identified according to Ridgely and Tudor (1989, 1994), and Sigrist (2006). Mites were collected directly from the nasal fossae, with the aid of brush and forceps, preserved in absolute isopropanol, and then brought to the laboratory. Samples were processed according to Henderson (2001), and were morphologically identified according to the keys proposed by O’Connor et al. (1991) and Naskrecki and Colwell (1998).

3. Results

Among the 76 Apodiformes from the Trochilidae family captured, there was a total of 12 different species. Table 1 provides a list of all the captured Apodiform species, and the results of infestation by nasal mites, grouped according to biomes. Overall, 20 female mites were collected and identified as being from the Rhinoseius genus (Rhinoseius spp.), as shown in figure 1.

Table 1 Apodiformes (Trochilidae) from Cerrado and Pantanal biomes of the Mato Grosso state between 2012 and 2014, quantified by species and biomes, and Rhinoseius spp. occurrence and abundance in these hummingbirds.

The term “hummingbird flower mite”, although little known, is used to define the relationship that occurs with Apodiformes (hummingbird), flowers and mites of the family Ascidae (Mesostigmata) (López-Orozco and Cañon-Franco, 2013). These mites have been described as parasitizing to Apodiformes and Passeriformes, and are identified into approximately 22 genera, and 60 species (Naskrecki and Colwell, 1998), with the most common genera being: Lasioseius Berlese, Proctolaelaps Berlese, Rhinoseius Baker and Yunker, and Tropicoseius Baker and Yunker (O’Connor et al., 1991; Proctor and Owens, 2000; Dusbabek et al., 2007).

According to MacChioni (2007) phoresy is the interaction between one species of animal that passively attaches to another species of animal, the relationship ranges from a state of quiescence, to life cycle synchronization. If the relationship involves hummingbirds, plants and mites, then the plants act as habitats, while the hummingbirds only act as carriers and dispersers for the mites, parasitism does not occur as part of the mites biological life cycle (Hunter, 1972; Guerra et al., 2010). Following this model, Rhinoseius spp. feed on pollen during the nymph stage, and nectar in the adult stage (Hunter, 1972), this food habit decreases the amount of food available in the environment for nectarivorous species, and also causes a negative impact on the reproductive dispersion of the plants carried by these hummingbirds (Heyneman et al., 1991; Lara and Ornelas, 2001; Velázquez and Ornelas, 2010). Thus, although phoresy is an interspecific relationship classified as commensal, it does have a negative impact, because there is less food available for the Apodiform species, and reduced reproduction in plants (Colwell, 1995).

The knowledge about phoretic mites is important, mainly for the development and conservation of biodiversity. It is important to consider that phoretic mites can cause indirect damage to the Apodiform population, and also to the reproductive dynamics of plants, and their ecosystems, in which these mites are inserted.

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